Songbird's Encore

 is an item in Bastard's Wound.

Description
Though the delicate clockwork constraining Sirin's head to this headdress remains as inscrutable as ever, she wears it more lightly, as if the burden of it has lessened. The gem at her brow catches the light and amplifies it before releasing it back into the world, pulsing in time with the Archon's songs.

Location

 * Automatically obtained at the start of Act 3 by talking to Sirin. You need to have visited Cairn's Passage and interacted with the stones there, then found the Ancient Oldwalls parchment in the Oldwalls, then given it to Sirin for inspection.